Wand of wishing

Zapping a wand of wishing, with non-negative Luck, is the only guaranteed source of wishes.

This wand is unusual because it can only be recharged once[1]. It always explodes if you try to recharge it a second time; other wands have a chance to be recharged multiple times without exploding. It is not possible to wish for more wishes, so if you wish for another wand of wishing, the second wand will normally come cancelled, which is useless. There is a 10% chance that you will receive an empty recharged wand of wishing, from which you can wrest the final wish.

Wands comprise 4% of all randomly-generated items in the main dungeon, 6% in containers, 5% on the Rogue level, and 8% in Gehennom. There is a .5% chance that a randomly-generated wand will be a wand of wishing, making it one of the least-generated wands. However, one wand of wishing is always located inside a chest inside the Castle.

The other source of charging is the Platinum Yendorian Express Card, but wishing for this to recharge your wand is a bad idea unless you are illiterate because Tourists will not receive it at all, and other roles cannot perform blessed charging with it, so 1-2 of your wand's potential charges might be lost.

Since Tourists can acquire the Platinum Yendorian Express Card on their quest, they may choose not to wish for a source of charging, and delay using their final wishes until they can complete their quest.

How to extract the maximum number of wishes follows:

Zap the wand until it reaches (0:0).

Blessed-recharge the wand (this will bring the wand up to (1:3), while an uncursed scroll would bring it to (1:d3)).

If you fear the RNG, you may want to identify the wand first in order to find out how many charges it has left, rather than zapping until "nothing happens"; although rare, there is no worse feeling than accidentally wresting the last charge out of a wand you meant to recharge. Never zap a wand of wishing while your Luck is negative, because there is a chance that your wish will be lost. ("Unfortunately, nothing happens.")[2] Note that wishing will reset your prayer timeout.

If you come across a wand with a base cost of 500 in a shop, it is frequently a good idea to zap it, particularly if you cannot pay for it; it is either a wand of wishing or a wand of death. If it's the former, you've got a wish; if it's the latter, zap it at the shopkeeper to keep it (and the rest of his stuff). Note that if you can't pay for the wand of wishing, you should consider wishing for a wand of death to zap the shopkeeper with. However, if you're not chaotic, make sure you wish for everything else you want first, as the murder penalty may cause your luck to be negative. And in any case, be careful of doing this in Minetown (or the Mall, in SLASH'EM), because it will anger all the guards on the level.